Juha Köykkä - Oulu

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Res Terrae, Ser. A 32, J. <strong>Köykkä</strong>, Sedimentology of the Mesoproterozoic Telemark basin-fills, South Norway: implications for sedimentation processes, depositional environments and tectonic evolution Skottsfjell, (8) Vindsjå, (9) Brattefjell lower member, (10) Brattefjell middle member, (11) Brattefjell upper member, (12) Svinsaga, (13) Ljosdalsvatnet & Robekk, (14) Røynstaul, (15) Morgedal, (16) Dalaå, (17) Gjuve, (18) Eidsborg, (19) Brunkeberg, (20) Transtaulhøgdi supracrustals, (21 & 22) Vallar bru & Heksfjellet, and (23 & 24) Skogsåa porphyre & Heddal Gr sediments. RST/LST: regressive/lowstand system tract, CTS: conformable trangressive surface, TST: transgressive system tract, MF: maximum flooding surface, HST: highstand system tract, R: transgressive ravinement surface. 70
Res Terrae, Ser. A 32, J. <strong>Köykkä</strong>, Sedimentology of the Mesoproterozoic Telemark basin-fills, South Norway: implications for sedimentation processes, depositional environments and tectonic evolution 7 Conclusions The conclusions summarize the sedimentological basin analysis presented in the thesis and main results achieved from the Telemark basin-fills. I The Telemark basin-fills represent a tectonic-sedimentary evolution from the extensional continental rift to the strike-slip influenced tectonic setting. The prove- nance studies indicate that the sedimentation basin was likely located near the Lau- rentia supercontinent and moved to its present location along sinistral strike-slip fault. II The evolution of the Rjukan Rift Basin can be subdivided into (i) syn-rift, (ii) late- syn rift, (iii) early-post rift, and (iv) late-post rift stages. Each stage was characte- rized by different volcanic-sedimentary patterns, where a fluctuating basin subsi- dence created an accommodation space for basin-fills during the pure extensional tectonics. The accumulated basin-fills indicate sedimentation in alluvial fan, braid- plain, fluvial, estuarine-lagoon, shallow marine and tidal environments. The lack of a deepwater sedimentation prism and oceanic crust, and the non-evolution to pas- sive margin setting strongly indicate that the rifting failed to complete the break-up of the continental crust. III The Telemark basin-fills strata are truncated by the sub-Svinsaga unconformity, which represents a ca. 170 Ma hiatus in the stratigraphic record, marking the boundary of evolution in the tectonic regimes. The sedimentological studies indicate that this boundary was closely associated with periglacial cold-climate processes and that the tectonic deformation and evolution was likely more intensive in different localities. IV The abrupt lateral lithofacies variations, coarse-grained alluvial fan sedimentation, intrabasinal unconformities, bi-modal volcanism, and basin margin faults strongly suggest a strike-slip influenced setting for the early Sveconorwegian units. The evolution possibly contains a sedimentary-volcanic transpression or extension stage to a non-volcanic and sedimentary dominated transtensional stage. The fault- ing and volcanism was probably activated either at a later stage during the basin evolution or in certain individual basins. 71
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RES TERRAE Publications of the Depa
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Juha Köykkä - Oulu

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